Grinding-machine.



L. W. BUGBEE.

GRINDING MACHlNE.

APPLICATION FILED AUG-21.1916.

1,Q82,@37, Patent-ed Oct. 22, 1918,.

2 SHEETS-SHEET 1.

WITNESSES. IN l/EN 70/? Hf/AN w augaf fig j whdu aw m A TTOR/VE KS L. W.BUGBEE.

GRINDING MACHINE.

7 APPLICATION FILED AUG.21, 1915- I 1 22 3? Patented Oct. 22, 1918..

2 SHEETSSHEET 2.

WITNESSES:

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LUCIAN W. BUGBEE, F SOUTHIBIRIDGE, MASSACHUSETTS, ASSIGNOR TO AMERICANOPTICAL COMPANY, OF SOUTHBRIDGE, MASSACHUSETTS, A VOLUNTARY ASSOCIA-TION OF MASSACHUSETTS.

GRINDING-MACHIN E.

J Specification of Letters Patent.

Patented Oct. 22, 11918.

Application filed August 21, 1916. Serial No. 116,038.

To all whom it may concern:

Be it known that I, LUCIAN W. BUGBEE, a citizen of the United States,residing at Southbridge, in the county of WVorcester and State ofMassachusetts, have invented certain new and useful Improvements inGrinding-Machines, of which the following is a specification.

My invention relates to improvements in grinding machines and hasparticular reference to a novel and improved machine particularlyadapted for use in the construction of bifocal lenses.

One of the leading objects of the present invention is the provision ofa novel and improved means for readily and accurately forming the minoror reading portion of a lens having a plurality of focal points.

A further object of the invention is the provision of an improvedmachine particularly adapted to hold and accurately position therein afinished lens or lens blank and facilitate the formation of a portionthereof to a diflerent curvature to change the lens from an ordinarysingle focus lens to a bifocal.

A further object of my invention is the provision of an improved machinewhich may be readily'adjusted to insure exact centerin or positioning ofthe centers of the two foci of the lens relative to each other and tofacilitate the formation of the second curve with a prism or othervariation from the power and curve of the major blank as desired.

Another object of my invention is the provision of a novel and improvedtool for operation upon the lens and a novel and improved means forinsuring a gradual turning movement of the tool to prevent scratching ofthe lens or formation of wavy surfaces thereon.

Other objects and advantages of my improved grinder should be readilyapparent by reference to the following specification taken in connectionwith the accompanying drawings forming a part thereof, and it will beunderstood that I may make any modifications in the specific details ofconstruction shown and described without departing from or exceeding thespirit of the invention.

Figure I represents a front elevation of the grinding machineconstructed in accordance with and embodying the generic principles ofmy invention. D

Fig. II represents a side elevation thereof.

F ig.. III represents a plan view of the lens supporting table andassociated parts, the remainder of the machine being shown in section ason the line III-III of Fig. II.

Fig. IV represents a sectional view as on the line IVIV of Fig. III.

Fig. V represents a bottom plan view of one of the grinding or polishingtools for use in connection with my improved machine. I i

Fig. VI represents a top plan View of one form of tool.

Fig. VII represents a sectional view as on the line VI-V I of Fig. V.

In the drawings, in which similar characters of reference are employedto denote corresponding parts throughout the several views, the numeral1 designates the base of my improved machine having rising therefrom thestandard 2 provided with the bearings 3 for the lens grinding spindle 4which is suitably provided with driving means, as the pulley 5, adaptedto receive a driving belt 6 for rotating the spindle.

Disposed beneath the spindle and concentrically located with respect tothe axis of the spindle is the bearing cup 7 preferably of substantiallyhemispherical form, adapted to receive the hen'iispherical supportingmember or bed 8, which is mounted for rolling movement in the cup 7, anysuitable means being employed to lock the bed in desired adjustedrelation to the cup, as for example the magnetic clutch or lockingmembers 9 shown in Fig. IV of the drawings, it being understood,however, that any desired equivalent of these members may been'iploye'd, and it being further understood that the essential featurein the mounting of the bed is that it shall be mounted for substantiallyuniversal movement, a hemispherical bed and cup having been hereillustrated on account of the ease of locking said parts in adjustedposition, but it will be understood that other equivalents such as adouble gimbal bearing or the like may be employed if preferred.

Fitting into dove-tail slots on the upper face of the bed 8 are theslides mounted for movement transversely of the-bed, while 'ngprojecting of stationary i and having ppleniental slide 13 l lensengaging incinurging the slide toward to resiliently clamp eei, asuitable locksprings sta iionury pins 12 V is 16 therebeti 1r 5mechanism such a: the set so ew ll servins; t lock the slide 13 inclamped position i securel retaining the lens when ositioned andcentered, and preinoi'enient thereof relative to ftw e uni erstood inconnection with I description that I have shown d a semi-finished or cutlens as ted within the holder and have described a lens hold-e2. adaptedof lens althoug e eniiloyed in conne A i t 'tLlQQl to any other suitableorin which will SifiiSIuCiOLl} anti retain it in desired posireinova aifii no sl curve of the under face The annulus is h a central poirt iyieldingly or re- 's ooint serving both he center of the lens l aidingin determinnoint on the original lens ninor por- 2O beininent with hegrim (i v u al on i c nierely necessary to locking member 1? and theloch- 21 for the carriage plate 11, to at the points 12 and 1 1- untilthe be placed therebetween the le s t ownwni'd to iiin'ilj; rest uposupport 18. Zhe movement it, ,i i i e r e carriage plate 1i i 1.1 mengieiinit oi o the carriage plate 11 with the slides will permit ofpositioning of the 1')I'Qli6lll'1l11@(l center exactly over the pointwhen the carriage plate 11 will be locked in position through thelocking member 21 and the lens being again firmly pressed downward ontothe annulus, will be locked into position by tightening of the lockingmember 17.

It is then desirable to adjust the lens according to whether a prism isto be ground in the minor portion face in or out, up or dowi, this beingaccomplished by rocking of the bed 8 in the cup 7, to bring the lensinto position where the aXis ot' the spindle iwill be normal to the lensor in desired 2121i! to the lens Where ie bed 8 is secured in t d"position b7; the suitable devices 9. The lens is now in position forgrinding.

To wind and ish new or minor 1 reterabl provide the s iucie. with the"ably adjustable crank whose onset relatii'eto the spindle adjusted asdesired to vary the size the n i or portion, said crank arin 22 havingdepending pointadupted to be enin the recess 2% of the 'rinding tool)lli IOll This button may be an ordisolid button or cloth coveredpolished utton such as .illus ste l in Fig. 1V

o and having merely the CQiCQ the pivot or it oi'ed polishing; buttialmovement to intial grinding it l ast with a plurality of grooves asillustrated in Figs, 1V and i these grooves leadg toward the center andfacilitating flow of the grinding fluid toward the ceit i= of the buttonand thus insuring a libera usntity of emery or other grinding iiuidbeing at all times within the tool or lens to j e ent scratching orinjuring the lens by the tool and insure rapid g inding.

in the form of tool illustrated in Figs. Vi and 1 have shown the buttonas comprising t 1e shell or grinding portion 25 recessed in its upoerface to provide the shoulder 27, and the projecting circumferentialflange :28 the button having the central countersunk recess or socket 29to receive the cone point 30 of the disk 31, the cone point beingslightly eccentric to the disk whereby the disk at one side will at alltimes contact with the flange 28 while being out of engagement therewithat the opposite side and the recess 2% being" eccentric to both the pin30 and the dish 31, as illustrated.

e erabl'y' form the inillil 'ilii insane? In the operation of myimprnwed grinding or polishing button the point 23 of the crank isengaged in the aperture 2 of the disk and a rapid spinning motionimparted to the tool 25 as an entirety, together with the crank onaccount of rotation of the grinding spindle I. In addition, however, tothe spinning or movement in a circular path of the button as an entiretyas carried around by the crank arm 22, there will be a spinning ortwisting.

movement of the button about the point 23 due to a certain variance inthe frictional resistance between the outer and inner portions of theengaging surfaces of the lens and button and also due to the fact thatas the button grinds down onto the lens there will be a certainfrictional engagement between the side of the button and the edge of thecountersink formed in the lens tending to operate as a planetary drivefor the button. Additionally, in the form of construction illustrated inFigs. VI and VII, there will be a gradual relative movement of the disk31 and grinding surface 25 due to the fact that the movement of thecrank engaged in the socket 24 eccentric to the disk :25, will cause acertain tilting or rocking movement of the disk 31 on the point 29, eachrocking movement temporarily throwing the frictional engaging edge ofthe disk off the shoulder 27 and flange 28, when the disk willmomentarily move without the butt-on, the further rocking movement ofthe disk again bringing it down into frictional locking engagement withthe button to further rotate the button, this movement operating then asan additional break-up to insure against wavy or defective surfacesbeing formed on the lenses ground.

From the foregoing description taken in connection with the accompanyingdrawings, the construction and operation of my improved bifocal lensgrinder should be readily understood, and it will be seen that it ismerely necessary to properly mount the lens to be ground within the lensholder and upon the support 18, to then shift the carriage and bed untilthe lens is the exact desired relation to the grinding spindle, thecurve of the bed and supporting cup being such that tilting movement issubstantially about the intersection of the axis of the grinding spindlewith the surface of the lens so that the tilting movement will not varysubstantially the position to be occupied by the bifocal segment on thesurface of the lens, and to then place a suitable grinding tool inengage ment with the surface of the lens and apply power thereto. Itwill be noted that to cause the relative feed of the grinding tool andlens I have shown the spindle 4: as vertically slidable and providedwith the spring 32 to actuate it toward the lens, a suitable latchmember 33 being employed to hold the spindle in raised position asdesired.

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-gradually fed from the tank onto the lens and will remain in the cup ortrough formed by the concave curvature of the original lens blank andthus insure a sufiicient supply of the grinding fluid being at all timeson the lens.

I claim:

1. In a machine of the character described, the combination with a base,of a lens carriage plate, slides supporting the carriage plate forlongitudinal and transverse movement relative to the base, lens clampingmeans on the carriage plate to secure the lens for movement with thecarriage plate, a grinding spindle, and a lens support mounted in fixedposition relative to the spindle for engaging the portion of the lens tobe operated upon irrespective of the adjustment of the lens with thecarriage plate.

2. In a machine of the character described, the combination with a base,of a tiltable supporting bed carried thereby, a lens we support fixedfor movement with the bed, and a lens holding device mounted for slidingmovement relative to the bed, said lens holding device spanning thesupport to retain the lens in engagement With the support.

3. In a lens grinding machine, the combination with a base, of atiltable bed carried by the base, a lens support rising from the bed, acentering point carried. by the support, means for clampingly securing alens in engagement with the support, and means for adjusting the lensand clamping means relative to the support.

4. In a machine of the character described, the combination with a base,of a tiltable supporting bed carried thereby, slides mounted upon thebed for transverse movement relative thereto, a lens support mountedupon the bed, av plate carried by the slides, lens rests carried by theplate,

a supplemental plate mounted upon the first plate, additional lens restscarried by the supplemental plate, yielding means for clamping a lensbetween said rests and locking mechanism for retaining the lens againstmovement thereof relative to the bed.

5. In a machine of the character described, the combination with a base,of a tiltable supporting bed carried thereby, 139

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mounzed upen the bed for rensverse relative thereto, a lens support ofan annulus mounted upon he ring; peint carried by the supurried by cueslides, lens rests 1 1' :he plate, a supplemental plate as first plate,additional lens V ihe supplemental pla ce 101' clamping a lens betweezl

